A variety of different industries use extractors to extract and recover substances entrained within solids. For example, producers of products from renewable organic sources use extractors to extract carbohydrates and/or oil from solid matter, such as soybeans, rapeseed, sunflower seed, peanuts, cottonseed, palm kernels, and corn germ. The matter is contacted with a solvent within the extractor, causing the desired product to be extracted from a surrounding cellular structure into the solvent. As another example, extractors are used to recover asphalt from shingles and other petroleum-based waste materials. Typically, the petroleum-based material is ground into small particles and then passed through an extractor to extract the asphalt from the solid material into a surrounding organic solvent.
Depending on the type of extractor used to perform extraction, the extractor can have one or more sections of screen along which material is moved during operation. For example, a percolation extractor may have a bed deck formed of a screen and a solvent distribution system positioned above the screen. In operation, feedstock material can travel along the bed deck from the inlet of the extractor toward the outlet of the extractor. As the feedstock moves along the bed deck, liquid solvent is discharged on top of the feedstock, causing the solvent to percolate through the feedstock and drain through the underlying screen. The solvent extracts different components from the feedstock as it percolates through the material.
In practice, the screens used in extractors can become plugged during the course of operation. Fine particulate from the feedstock being processed may agglomerate and reduce or completely block the pores of the underlying screen. As the porosity of the screen decreases over time, the extraction efficiency of the extractor may be reduced. To restore efficient operation, the operator of the extractor may be required to shut the extractor down, remove residual feedstock and solvent from the extractor, and manually clean the extractor screens. This can be a costly and time consuming process.